Field of the Invention
The present invention relates, in general, to computers and, specifically, to computer peripherals, such as printers, multiplexers and CRTs, which are connected to computers, and, more specifically, the test equipment for testing the operation of computer peripherals.
Computer systems typically include a central or main computer which is connected by various data, address and control busses to a plurality of computer peripherals, such as printers, multiplexers and CRT terminals. It is often necessary to test each peripheral and its attached data communication cable for proper operation as well as to locate and isolate any malfunctions in the overall computer system in the computer mainframe or computer peripheral.
Previously, computer manufacturers have provided such testing via diagnostic tapes used on magnetic tape drives and run under control of a main computer. Such testing runs various test programs which check the general operation of the subsystem consisting of a peripheral, cable and controller as a whole without regard to the treatment of each component as a separate entity. Further, the testing of the peripheral is typically done offline, that is, when the main computer is not running other programs.
Computer peripherals come in a variety of types and utilize different data transfer formats, such as serial or parallel as well as various serial baud transmission rates, and parity check and stop bits formats. Further, some peripherals are labeled data communication equipment (DCE) or data terminal equipment (DTE) each having their own serial data transmit and receive pin configurations.
Testing such peripherals has been difficult since most computer controlled diagnostics only offer a go/no go means of testing the entire subsystem. No indication is given as to the failing component. Further, there is the online/offline problem which requires the main computer to be run offline to test the peripherals; wasting valuable system time.
What is needed is a computer peripheral tester which may be utilized to test a peripheral and/or its cable when the computer is online and running other programs. It would be desirable to provide a computer peripheral tester which is portable and easily attachable to a computer peripheral. It would also be desirable to provide a computer peripheral tester which can be easily employed to detect malfunctions in a computer peripheral or in the data communication cable attached to the peripheral. It would also be desirable to provide a computer peripheral tester which is versatile in use in that different peripheral characteristics may be software selected to configure the peripheral tester to the data transmission characteristics of a large number of different types of computer peripherals. Finally, it would be desirable to provide a computer peripheral tester which is programmable for either serial or parallel data communication with a computer peripheral.